Wireless ad-hoc networks: Strategies and Scaling laws for the fixed SNR regime

TL;DR

This paper analyzes throughput scaling laws in fixed SNR wireless ad-hoc networks, showing collaborative strategies outperform multi-hop in certain regimes, with specific scaling laws derived for each approach.

Contribution

It introduces new throughput scaling laws for fixed SNR ad-hoc networks and compares the effectiveness of collaborative versus multi-hop strategies.

Findings

Collaborative strategies achieve a $ ho(n) = O(1/n^{1/3})$ scaling law.

Multi-hop strategies achieve a $ ho(n) = O(1/ oot{2}n)$ scaling law.

Collaboration benefits are limited when SNR vanishes with network size.

Abstract

This paper deals with throughput scaling laws for random ad-hoc wireless networks in a rich scattering environment. We develop schemes to optimize the ratio, $\rho(n)$ of achievable network sum capacity to the sum of the point-to-point capacities of source-destinations pairs operating in isolation. For fixed SNR networks, i.e., where the worst case SNR over the source-destination pairs is fixed independent of $n$, we show that collaborative strategies yield a scaling law of $\rho(n) = {\cal O}(\frac{1}{n^{1/3}})$ in contrast to multi-hop strategies which yield a scaling law of $\rho(n) = {\cal O}(\frac{1}{\sqrt{n}})$. While, networks where worst case SNR goes to zero, do not preclude the possibility of collaboration, multi-hop strategies achieve optimal throughput. The plausible reason is that the gains due to collaboration cannot offset the effect of vanishing receive SNR. This suggests that for fixed SNR networks, a network designer should look for network protocols that exploit collaboration. The fact that most current networks operate in a fixed SNR interference limited environment provides further motivation for considering this regime.